Table iv



INORGANIC GEL-THICKENED LUBRICANT OF GOOD TEMPERATURE SUSCEPTIBILITY ANDggqNgMIC WATER STABILITY CHARACTER- Ernest C. Milberger, Maple Heights,Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, :1corporation of Ohio No Drawing. Application February 8, 1954 Serial No.409,006

6 Claims. (Cl. 252-28) This invention relates to an aerogel thickenedlubricantresistance 'teriorate readily in the presence of water,presumably due to the high solubility of the soda base soap in water.Calcium soap greases have better resistance to water but tend to losetheir consistency or thin out at 2,828,260 Patented Mar. 25, 1958 2excellent temperature susceptibility properties and ex cellent dynamicwater-resistance, attributable to the presence of the alkylol or aminoimidazoline and the polyalkylene glycol diether.

The polyalkylene glycol diethers are characterized by the followinggeneral formula:

R[?O?CHR1[CHR2]1|*]OR3 where n is an integer having the'value of'one ormore, preferably one, two or three, x is an integer taken in sufiicientnumber to produce an ether having the prescribed viscosity, R and R arehydrogen or lower alkyl groups, and R and R are each lower alkyl groups.When n is one, preferably at least one of R and R is a lower alkylgroup, preferably methyl. The lower alkyl group can have from one toabout five carbon atoms such as methyl, ethyl, propyl, butyl or amyl andcan have either a straight or branched chain. Preferably, one of R and Ris hydrogen one is a methyl group, and R and R can be, methyl, ethyl'orisopropyl.

Within the above Formula 1 and worthy of especial mention are the mixedethers of the types:

elevated temperatures. Both types of soap base greases where a, b, and.x are integers taken in suflicient numbreak down at temperatures of theorder of 300 to 400 F. and this breakdown is accompanied by anirreversible change in the grease structure so that on cooling thegrease is found to have lost its greaselike characteristics. The aerogelgreases usually are far superior to the soap base greases in stabilityat high temperatures as the following'table shows:

However after heating at high temperatures some aerogel greases tend tothin out-upon stirring and this is undesirable in field applicationswhere a grease, is agitated'or worked while subject to a hightemperature. Aerogel greases also reveal an unsatisfactory dynamic waterresistance and this again is unsatisfactory in field applications wherethe grease is agitatedor worked in the presence of water. a The greasemay emulsify with water to the point of inversion to an oil-in-wateremulsion, at which point the grease characteristics are lost.

In accordance with the invention water-insoluble oilmiscible or-dispersible polyalkylene .glycol diethers characterized by aviscosity-at 100 F. within the range of 40 to 500 SSU are employed inconjunction with an alkylol or amino imidazoline in thickenedlubricant-compositions comprising a lubricating oil thickened with anonabrasive inorganic thickening or filling agent and particularlyfinely divided silica, a silica aerogel being illustrative. Thethickened lubricants so prepared have her to produce .an ether havingthe prescribed viscosity, an n and 1 and 1. and R2 and. R2. cann e thsame or different, and are defined as in Formula 1. Preferably, when thea units are OCH CH and the b units OCH2CH ZHs the ratio of azb is to 25of a to 10 to of b.

These ethers are obtained by reaction of the alkylene oxide with wateror a glycol, and with a monohydric alcohol, desirably in the presence ofa catalyst. The reaction which takes place seems to be a simple additionwherein the alkylene oxide is converted to the corresponding oxyalkylenegroups or radicals. The glycol may itself be prepared by reaction of thealkylene oxide with water. Thus, water can be regarded as the ultimatestarting material. The molecular weight of the polymer obtained willdepend upon the relative proportions of alkylene oxide, water andnionohydroxy aliphatic alcohol.

From various analyses it has been determined that these polyalkyleneglycol others are complex mixtures of .compounds having polyoxyalkylenechains of different lengths and difierent internal configurations, andalthough the materials are characterized as diethers, theymay contain asmall'proportion of chains having hydroxyl groups at each end and ofchains having one alkyl group at-each end, i. .e., monoethers. If mixedalkylene oxides are employed as the starting material the chains willcontain complex mixtures of the mixed alkylene oxide radicals in variouscombinations, depending upon the relative proportions of the alkyleneoxides, and a given chain may have several oxyalkylene units of the sametype together orintermingle with othe xyal yl n u its in any o eor-combination. Thusthe above formulae for the mixed ethers are merelysuggestive of the types of combinations t may b f n The imp rtant crierion rom th andp in o the invention isthe viscosity of the ether, andthis should be within the range from 40 to 500 SSU at F.

Polyethylene and mixed polyethylene-1,2-propylene glycoldimethylethersare preferred.

Thus it will be understood that there can be employed in accordance withthe invention mixtures of these glycol others with monohydroxymonoethers and even dihydroxy compounds which are present in the mixturefollowing condensation and/ or etherification of the alkylene oxide, butat least the major proportion and preferably upwards of 85% is thediether. Reference is made to U. S. Patent No. 2,425,845, to Toussaintet 211., dated August 19, 1947, which describes methods for themanufacture of the glycols and to U. S. Patent No. 2,425,755, to Robertset al., dated August 19, 1947, which describes the preparation of themonoethers. The diethers are obtained by methodsanalogous to themonoethers, using twice the amount or more of the monohydric alcohol.

The imidazoline should be surface-active, oil-dispersible andwater-insoluble and has the following structure:

Many of the compounds having the above general structure are alsocapable of improving the high temperature stability of lubricating oilsthickened with inorganic thickening or gelling agents, such as silicaaerogels.

In the above formula, R is a hydrophilic group. Especially satisfactoryhydrophilic groups are alkylol groups and aliphatic, cycloaliphatic ormixed cycloaliphatic amino groups having at least one basic nitrogenatom.

The alkylol group can bear one or more hydroxyl groups.

The amino group preferably has at least two basic nitro .gen atoms,which can be primary, secondary or tertiary, in any combination of thethree. Where one or more of the nitrogens is primary, i. e., NH they canbe attached at any position in an aliphatic chain or on a cyclic ring.Where one or more of the nitrogens is secondary or tertiary, i. e.,

they can be substituted in a straight or branched aliphatic .chain, orin heterocyclic ring, which can itself bear alkyl, alkylene,hydroxyalkyl or hydroxyalkylene groups, desirably in the 'l-position, asin the above imidazoline ring. See U. S. Patent No. 2,655,476, datedOctober 13, 1953, to Everett C. Hughes and Ernest C. Milberger.

Thus R can be a hyd-roxyethyl group, a mono-, dior triethylene aminogroup, a l-alkylene-imidazoline group, or a l-alklylene aminoimidazoline group.

R is an alkyl, hydroxyalkyl, alklyene or hydroxyalkylone group.

R, which is derived from an acid, can have from eleven to twenty-onecarbon atoms, such as undecyl, tridecyl, abietyl, pentadecyl, undecenyl,heptadecyl, ricinoleyl, and heptadecenyl.

The alkylol irnidazolines are prepared by reaction of.

aliphatic acids and hydroxy diamines followed by cyclization, in thefollowing way:

:a'ooou RNHCH CHgNH; n-1v N 21120 non-abrasive.

line, and analogous compounds as described in application Serial No.240,452, filed August 4, 1951, now U. S. Patent No. 2,711,393, patentedJune 21, 1955, have been found to be particularly effective alkylolimidazolines in the thickened lubricants of the invention.

The amino imidazolines are prepared by reaction of aliphatic acids andpolyamines followed by cyclization in the following way:

Amino imidazolines in'which R has two basic nitrogen atoms and from fourto about twenty carbon atoms, such as diethylene'diamino and triethylenetriamino, and the alkyl-substituted N-alkylene and N-alkyleneaminoimidazolines (wherein R is attached to the imidazoline nucleus of thegeneral formula through the N-alkylene or Nalkylene-amino group), arereadily available and are preferred. The chain length for R is dependentupon the basic (polar) character of the group, the larger the number ofcarbon atoms, relative to the number of amino nitrogens, the more thegroup takes on the character of a hydrocarbon'and loses its basic oramine character. An upper limit of about five carbon atoms per aminonitrogen is indicated by this requirement, with about a maximum ofthirty carbon atoms for the R group.

The amino imidazolines described in U. S. Patent No. 2,655,476 have beenfound to be particularly effective in the thickened lubricants of theinvention.

The presence of the polyalkylene glycol ether in an amount to obtainimproved high temperature and dynamic water stability does not markedlyaifect the consistency of the thickened lubricant, i. e., the amount ofthe inorganic gelling agent to impart a given consistency to thethickened lubricant is not materially modified. Furthermore, theinclusion of the polyalkylene glycol ether will not efiect a change inthe consistency of the thickened lubricant upon storage.

Due to the inorganic nature of the gelling agent, the thickenedlubricant has excellent storage stability. This is to be contrasted withthe heat susceptibility and deterioration of fatty materials insoap-base greases.

The preparation of the grease is simple and readily adaptable tocontinuous operation, as contrasted with the involved grease-makingtechniques which are often considered in the industry as an art.

The oil stock used in making the thickened lubricant may be widelyvaried, as contrasted with present greasemaking requirements in whichthe oil in many cases must meet certain critical specifications.

In addition, the avoidance of the use of soap permits :the manufacturerto be independent of the fat supply, which is important in periods inwhich fats and soaps are scarce and, many times, of pronouncednon-uniformity.

The inorganic gelling agent to be used in making the thickened lubricantin accordance with this invention may be any inorganic material whichforms a gel with a lubricating oil and which is so finely divided as tobe The preferred materials are the aerogels, which may be formed fromany material not incompatible with oil, such as silica, alumina, andother gel-forming metal oxides.

A series of silica aerogels which can be used as the inorganic gellingagent of theinvention are manufactured by Monsanto Chemical Company andmarketed under the trade name Santocel. 7

Santocel Cis prepared from a sodium silicate solution sets to form ahydrogel. The by-product sodium sulfate is washed out by repeatedwashings with water. The continuouswater phase in this 'hydrogel is thenreplaced by continued Washing with alcohol until an alcogel is formed.In order to remove the liquid phase without a collapse of the gelstructure, the alcogel is placed in an autoclave which is heated abovethe critical temperature of the alcohol and the pressure is allowed toincrease to a point above the critical pressure of the alcohol. The ventvalve is opened and the alcohol allowed to escape. Under theseconditions, the silica gel structure remains practically undisturbed andthe liquid phase of the gel is replaced with air. The material is thenreduced in particle size by blowing it through a series of pipescontaining sharp bends with jets of compressed air. Santocel C has asecondary agglomerate particle size of about 3 to 5 microns.

Santocel A is prepared as set forth for Santocel C up to the point ofremoval of the product from the autoclave. This material is run througha continuous heating chamber where it is heated for /2 hour to atemperature of about 1500 F. to eliminate the last traces of volatilematerial. It is then broken down in a reductionizer or micronizer to aparticle size of about & inch in diameter. The solids content of theoriginal hydrogel used in preparing Santocel C is approximately higherthan that of Santocel A.

AR is a modification of A, differing only in that the material isreductionized to about the same particle size as C, approximately 1 to 6microns in diameter.

ARD is a modification of AR, difiering only in that ARD is densified byextracting air under vacuum, and therefore has a smaller volume than AR.

AX is an A which has not been devolatilized.

CDv is a Cwhich has been devolatized as set forth for A. CDv isreductionized before being devolatilized.

CDvR differs slightly from CD; in that the CDvR has been devolatilizedjust after heating in the autoclave and then reductionized. It differsfrom CDv in that the latter is reductionized before being devolatilized.

The primary differences between the As and the Cs are as follows:

(1) The Cs are prepared from a'sodium silicate solution containing 25%more silica than the As. Therefore, in general the As are lighter andcomposedof smaller .particles than the Cs,

(2) The As have undergone a devolatilization step in their preparation.

The following are the bulk densities of preferred'silica aerogels:

Density, grams per ml.

AR 0.029 ARD 0.056 to 0.064 C 0.082

In general, AR and ARD show superior gelling ability and the As ingeneral are better than the Cs. Silica aerogels which have beendevolatilized generally have a higher gelling efliciency than theundevolatilized aerogels. Other types of inorganic gelling agents whichmay be used include a Fumed Silica marketed by B. F. Goodrich Company.It is finely divided and appears very much like an aerogel. It is madeby a combustion or vaporization process, as a source of white carbonblac for the rubber industry. The particles are several microns in sizeand porous in nature.

Another material is Linde Silica Flour marketed by Linde Air ProductsCo. It is very similar in physical appearance to the silica aerogel. Theparticle size of the silica is purported to be 0.01 to 0.05 micron andto be manufactured by burning silicon tetrachloride and collecting thecombustion product on cool plates analogous to the production of carbonblack. The particles are thought to be aggregates or clusters ofparticles rather than of sponge-like character.

Still another inorganic gelling agent known is Ludox 6 silica from DuPont which is known as a silica sol, and silica derivatives thereof. 'Ithas a particle size of the order of 0101 to 0.03 micron.

The silica from Columbia-Southern Chemical Corporation also is useful.These have the following properties:

Wet screen retained 325 mesh, percent .In preparing thickened lubricantsit is necessary to remove the water from the sol and replace it with anoil. This is possible by formulating the lubricant and removing thewater by flash distillation'orazeotropic distillation.

No attempt is made to enumerate all of the inorganic gelling agentswhich will be suitable, nor to present examples of all of them since thenovel aspects of the invention reside in water-proofing the lubricantrather than the use of novel gelling agents, per se.

The lubricating oil to be used in the process may have any lubricatingviscosity. It may be raw oil, acid-refined, or solvent-refined, asrequired for the particular lubricating need.

Tlre nature of the base oil has been found to make little difierence inthe relative consistencies of the thickened lubricants andconventionally (acid) refined oils produce slightly thicker lubricantsthan solvent refined oils. Excellent working stability is obtainedregardless of the type of the base oil. An increase in the viscosity ofthe base oil, as might be expected, brings increased viscosity to thethickened lubricant and minimizes bleeding. The change is'relativelysmall and fairly linear. The viscosity of the oil does not atfect theworking stability of the lubricant.

The relative proportions of the inorganic gelling agent and the oil willvary somewhat depending upon the desired body in the thickenedlubricant, the gelling ability of "the inorganic gelling agent and theviscosity of the oil used. It has been noted, for instance, that withthe Linde Silica Flour, the lubricants are somewhat harder, i. e., havea lower penetration than lubricants containing the same weight ofSantocel. Lubricants made with low viscosity oils require a somewhatlarger amount of the inorganic gelling agent to give a lubricant of thesame penetration. The thickened lubricant may vary in consistency fromthe consistency of a slightly thickened oil to a solid-or semi-solid ofgrease-like consistency. In general, the amount of the inorganic gellingagent falls within the range of 5 to 20%, and in most cases would fallwithin the range of 7 to 12% by weight of the thickened lubricant.

The amount of the inorganic gelling agent, as might be expected, aifectsthe consistency of the thickened lubricant in that an increase in itsconcentration brings a corresponding increase in consistency. The rangeis fairly linear and the amount of the gelling agent can be selectedwith relation to the consistency desired in view of the information inthe following examples. While the diiference is slight, the lubricantsmade with lower concentra tions of gelling agent possess better workingstability, while lubricants with larger amount of gelling agent showslightly improved temperature susceptibility characteristics. Thebleeding tendencies are decreased by increasing concentrations of thegelling agent.

In general, the properties of the thickened lubricants are remarkablyindependent of the composition variables and are not critical. Therelative concentration of the gelling agent effects the most significantalteration, parmeats ticularly with regard to the final consistency ofthe product. This permits the manufacture of thickened lubricants havinga wide variety of consistencies; p A wide variety of water-insolublepolyalkylene glycol diethers can be employed in accordance with theinvention. The molecular weight and chain length of the diether are notcritical except as they attect viscosity. Any polyalkylene glycoldiethers having a viscosity at 100 F. within the range of 40 to 500 SSUcan be employed in the composition of the invention.

The following are a few typical polyaikyiene glycol diethers inaccordance with the invention: 1 R-[O-OHr-OH-h-OR:

R[O OH2CH2CH2 1zO 3 n-to-onion-pom 2H5 R[CHzCH2CHaCHz] OR3 R[OCHOH-]z 0Rs JHa CH3 R[OCHzCHOH2l:OR3

(3H3 R[[O QHrOHqh-[O 011 531115], 0 Rs CH3 R-[[O OH GHaCH2][OCHz(I3H]b]zORa CH Exemplifying specific diethers within the scope ofthe invention are the Ucon DLB and DLB-X series of polyalkylene glycols,available from the Union Carbide and Carbon Corporation. These are mixedpolyethylene-1,2- propylene glycol dimethyl ethers, of the form of No.7,

for a few weeks or months it may display excellent water resistance.Preferably, from 4 to 14% imidazoline by weight of the aerogel is used,as such amounts usually impart excellent Water resistance at once. Acheap compound, of course, can be used in much larger quantities thancan an expensive compound, at the same total cost for the lubricant.

In some instances, the thickened lubricant may not display a long lifewhen used continuously at high tempera-tures. A breakdown in hightemperature stability at high temperatures if it appears is due to adecomposition, through oxidation,and in such circumstances, it isdesirable to include an antioxidant in the composition. Conventionalamine antioxidants which are more readily oxidized than the componentsof the lubricant can be employed for this purpose.Tetramethyldiaminodiphenylmethane, available under the trade name CalcoMB, is a particularly desirable antioxidant. Only small quantities arerequired, and ordinarily an amount ranging from 0.1 to about 1% byweight of the thickened lubricant is ample. There is no reason to employmore antioxidant than is necessary to produce the desired effect, butexcessive amounts do no harm and amounts up to 5% can be used, ifdesired.

' The composition is made simply by mixing the inorganic gelling agent,the oil, the polyalkylene glycol diether, the cationic water stabilizerand the antioxidant in any order or manner.

In one embodiment, the polyalkylene glycol diether and, desirably, thecationic water stabilizer and antioxidant, can be incorporated with theinorganic gelling agent either by mixing directly, or if desired, bydissolving them in a volatile hydrocarbon solvent, such as pentane,adding oil, mixing the solution with the inorganic gelling agent,

above, which have the followlng properties: and then evaporatmg thesolvent.

TABLE II DLB-144E Standard grade DLB-47-E DLB-67-E DLB-50-B DLB-l-BDLB-265-BX DLB200B Viscosity:

Saybolt seconds at 2. 52 9. 25 10. 76 s 43. 93 57. 22 109 1, 350 2, 465270 4, 500 10, 300 905 159 157 149 Pour point, F. (A. S. '1. M.13-97-39) -70 76 72 Flash point, open cup, F. (A. S. T. M. D-92-45). 270395 485 Do 335 455 555 Density, g./cc. at

The polyalkylene glycol diether should be oil-dispersible.

The polyalkylene glycol diether is incorporated in the thickenedlubricant in an amount to impart high temperature stability to thegrease. Ordinarily, a concentration of polyalkylene glycol dietherranging from 0.25 to about 2.5% by weight of the thickened lubricantgives satisfactory results. There is no reason to employ morepolyalkylene glycol diether than is necessary,.but excessive amounts dono harm, and amounts up -t-oj5% or even higher have been successfullyemployed.

In general, the concentration of the .imidazoline should at least about2.5% by weight of the aerogel but Wiii vary depending upon the waterstabilizing efiect desired,

the nature of the particular compound selected, the

amount and nature of the gelling agent used, and the economics involved.Both static and dynamic water resistance tend to increase with time, sothat anamount of imidazoline may be inadequate to impart the desiredwater resistance at once, yet after the grease has aged nique can beemployed, and, if desired, the mixture can be homogenized in a colloidmill, although this is not necessary.

The mixing temperature is not critical, but is preferably in the rangeof F. to about 250 F. At higher temperatures grease yield is affected.Mixing temperatures of to F. are preferred.

, Mixing is. continued until the components are thoroughly dispersed inthe coil and the consistency has attained the desired level. Any type ofmixingis satisfactory. High shear supplemental mixing at a high temoil,gelling agent,-imidazoline and polyalkylene glycol diether. Any of thematerials conventionally added to lu- :sion formed. was-noted. Whethertheemulsion was an oil-in-water .or waterin-oil type was readilyapparent, for the waterbricants and greases can be included. Theexpression consisting essentially of as used herein isintended to referto the components which are essential to the composition, namely, theoil, the inorganic gelling agent, the imidazoline, and the polyalkyleneglycol diether, and the expression does not exclude other componentsfrom the ccmposition which do not render'it'unsuitable for'lubrication,such materials being, for instance, the antioxidant, high polymers tomodify viscosity-or viscosity index, materials to impart tackiness,lubricating solids such as graphite, antioxidant additives, corrosioninhibitors of various types, sulfur, additives to render the lubricantsnitable'for use in gears, for cutting, grinding, etc.

The following examples illustrate preferred embodiments of theinvention. In the examples 'which follow the high temperature stabilityof the grease was determined by measurement of micropenetrations beforeand after heating to 400 F. in the block test. The grease was preparedfor the determination of high temperature stability by placingapproximately 100 cc. of grease in a 150 ml. beaker. The beaker washeated to the test temperature in an aluminum block furnace. Thisfurnace consisted of a solid block of aluminum heated by internalelectrical heaters.

Six holes, each large enough to accommodate a 150 cc. beaker, weredrilled in the 'top of the block, together with .a thermocouple, so thata measure of the temperature of the block could be obtained. In thismanner, six beakers could be heated simultaneously. The beakerscontaining the grease were placed in the aluminum furnace and heldthereuntil the equilibrium temperature of the grease reached 400 F. Thesamples were stirred five-minute intervals during heating. After thisthe grease was allowed to cool to room temperature overnight and thenwas stirred vigorously with a spatula. "Micropenetration measurementswere obtained on the grease before and after the test procedure. Thecycle was repeated as many times as desired and the results areexpressed by plotting'the actual penetration against the number ofcycles.

The static water stability was determined as follows: A 2 x 2 inchstainless steelgplate was coated with a uniform layer of the grease,following which the coated plate was immersed in a beaker filled withtap water and boiledforthirty minutes.

The dynamic water resistance of the grease was determined as follows:One hundred and fifty grams of grease wasweighed into the ASTM greaseWorker cup. The grease then was worked 300 strokes after which a "Shellpenetration was obtained. Fifty percent water by I weight of thegreasewas added, followed by asecond 300 stroke working cycle. A Shellpenetration was again obtained and anobservation made of the type ofemul- If free water remained unemulsified this in-oil emulsion was.shinyin appearance while'the oil-in- .good dynamic water resistance if,at'the conclusion of the second 300 stroke working cycle, in thepresence of water, the emulsion had not inverted, i. e., the emulsionremained of thewater-in-oil type, whether or not the water added hadbeen completely emulsified. Dy-

namic water resistance was considered excellent if inversionof-theemulsion had not occurred at the end of the third 300 strokeworkingcycle, in'thepresenceof water.

l -he' following results are typical of the application of this test toconventional "greases:

Lithium hydroxy- 129 146 '10 TABLE III Shell penetrations tial H20 1120W/O. Consid erable free water.

stearate.

Aluminum 155 166 Lime 182 Free water. W/O. Barium 141 Do.

Soda... Do. Aerogel (Santocel Emulsion inverted to 0/W ARD).

'W/O means water-imoil emulsion.

2 O/W means oil-in-water emulsion.

These results show that the soap base greases tested were resistant towater, but the areogel grease was not. Accordingly, anaerogel-basegrease that passes the test can be regarded as the-equal ofa-soap baseugrease in dynamic water resistance under thesetestconditions, which closely approximate field conditions.

The ability of the grease "t'o'emulsify with free water to some extentis desirable, and therefore in evaluating the test results it is notnecessary that the grease emulsify with water, but merely that it notemulsify with water to the point where inversion to an oil-in-wateremulsion occurs.

The working or mechanical stability ofthe greases was evaluated by10,000 strokes working at room temper- ,ature in the ASTM grease workerand by four hours at room temperature in a grease working assemblywherein the greases'ample was subjected to the severe working affordedby close intermeshing gears in an enclosed space. This approximates manyfield conditions for general ball and roller bearing and transmissiongreases. The measurements include a Sohio'micropenetr-ation of thegrease before working, a Sohio micropenetration after working, plus aSohio micropenetration after the grease has been allowed to stand forapproximately twenty-four hours, and another after the set up in greasebody has been disturbed by vigorous stirring with a spatula. The lasttwo measurementsofEer further data on the ability of the greases toresist mechanical breakdown.

Exa'mples'l io 10 Percent Santocel ARD 9.0. Ucon lubricant 2.0. Amine 0"Amount indicated in table below. Paratac 2 a 1.0. Paraflow 3 0.5.Ortholeum 0.5. Solvent extracted bright-stock (2000 S SU at 100 F.) 589.2.

1 1-,B-hydroxyethyl-2-heptadecenyl-imidazoline.

An isobutylene polymer sold by the Enjay Company, Inc. and commonly usedin compoundinggreases.

A Friedel-Crafts reaction product, useful as a pour point depressant andsold by the Enjay Company, Inc.

' An antioxidant for mineral lubricating oils. i

46.5 volume percent solvent-extracted bright stock, 78 SSU at 210 F. and53.5 volume percent solvent-extracted bright stock, 250 ssu at 210w.

The oil solu'ble additives, i. e., the Paratac, Paraflow and Ortholeum300, were dissolved in the oil. The oil was brought to 95 F., the. Amine'0 and Ucon added with thorough mixing and then the'Santocel was blendedin as rapidly as it was absorbed in the mixture. The total mixing timewas sixty minutes at the temperature indicated in the table.

- TABLE IV Temp., F. Final ASTM penetration Example Percent Uconpolygrease Initial 24 hr. No. Amine mer temp., Shell Shell 1 InitialFinal 1 pen. 0 60 oil bath oil blend strokes strokes 0 DLB 190-B 100 99100 155 165 325 325 4 DLB 190-B 95 95 93 157 170 332 326 8 DLB 190-B 9798 95 162 179 337 339 12 DLB 190-B 97 95 96 157 190 341 349 14 DLB190-13 95 95 94 185 195i 352 '352 8 DLB 50-B 96 96 95 152 168 322 318 8DLB l44-E 96 95 109 168 182 337 334 DLB 100 95 102 105 118 283 295 1Based on weight of Santocel ARD.

The table shows that in many cases the grease yield decreases as theamount of Amine 0 increases and this is a linear decrease as is evidentwhen the results are plotted on a graph. It would be concluded from thisdata that the smallest amount of Amine 0 required to give the desiredWater resistance should be employed.

The dynamic water resistance of these greases was TABLE VI evaluated bythe tests described above and are summarized test bel w; Example No.

TABLE 2m) m) 400 Dynamic water resistance 241 258 265 E. 2 22. 22.

cell 2 5 No. Amine Shell pens. 285+ 285+ 285+ 0" 1 Comments 285+ 285+285+ 285+ 285+ 285+ orig. 100% 285+ 235+ 285+ 285+ 285+ 285+ 285+ 285+285+ 1 0 Oil-m-water emuls1on-invers10n:c0m- 285+ 285+ 285+ pletebreakdown of grease. 272 285+ 285+ 2 4 Nearly inverted-free unemuLHaO.253 285+ 285+ 3 8 162 146 70% Water-in-oil emulsion% tree 235+ 285+ 285+unemul. H2O. 285+ 285+ 285+ 4..-" 12 157 149 50% Water-in-oilemulsion-50% free 5 14 185 197 a i it? 11 111 707 n 0 a crime em sion'ee uiiemul. 1120 0 The working stability of Examples 1 to 7 was deter-8 152 146 ZfiQLfiRQ? emulsln 25% free mined by the four hour test in thegear grease worker. 7.- 8 168 144 80% Waltlzer-in-oil emulsion-20% freeThe results obtained appear in the following table:

11119111 2 8"--- 10 136 122 Water-in-oil emulsiorr-free unemul.

1120. TABLE VII 113 1 rats 1: lARD.

on E g t 0 an ace Sohio micropenetration Gain in It is evident that 8%Amine O by weight of the E 1 N penetration Santocel was sufiicient toimpart good water resistance. mmpe The results for Examples 3, 4, 5, 6,7 and 8 are to be Original \Zl d. At rest 2: 1ers lfl 'd. 2x 4 1 12contrasted with Example 1 which did not contain Amine s e s e 0 but didcontain 2% of the Ucon lubricant. This j 115 157 119 170 42 .55 showsthat the Ucon lubricant alone, even at a concen- 101 110 100 12g 9 27 i122 152 125 201 30 79 tration of 2%, is not able to impart the necessarydynam c 132 156 1 15 191 24 59 water reslsta nce- 115 196 147 217 79 102As an additional comparison two greases were prepared E2 122 +32 $3 acontaining 5 and 15% Amine 0, respectively, by weight of the Santocel,and no Ucon oil. These greases had the following composition:

Example 9 Example 10 Percent Percent Ortholeum 300 0.5 0.5 Solventextracted bright stock (78 SSU at 21 The changes of penetration shown inthe table are of an order of magnitude indicating satisfactorymechanical stability.

These results show that greases containing Amine 0 alone even in amountsas high as 15% by weight of the Santocel or a Ucon lubricant alone haveeither satisfactory dynamic water resistance or satisfactory hightemperature stability, but not both. On the other hand, greasescontaining both the Amine O and the Ucon oil have excellent static anddynamic water resistance as well as good high temperature susceptibilityproperties even though the amount of Amine O is as low as 8% by weightof the Santocel and the Ucon oilis in the same amount as when usedalone. Evidently in the presence of the Ucon oil the Amine O is moreeffective in smaller amounts to impart dynamic water resistance whilenot affecting high temperature stability. The same effect is notobtained when diethylene glycohmonoethyl t v 13 V alkylene glycoldiether's-j of .higher molecular weight. [This is shown bythe following:i I v V greases we're prepared .having the. following formulation: 1

useless.

The results showthat with Carbitol at least 10% Very goo 1 Based onweight Santocel ARD.

- Amine O is necessary for satisfactory performance in Example? 11 t 6the static boiling water and that at least 14% is necesi Pe n sary inthe dynamic water test. This shows that Santocel ARD 9.0 Carbitol,diethylene glycol monoethyl ether having two i v (diethylfilna glycol nethylene glycol units. is not as effective as'the higher ethyl ether)2L0 in polyalkylene glycol diethers such as the Ucons, which are Amine OA o nt indicated polymers of ethylene'and 1,2-propylene glycol units, inf A ia belOW- cooperating with the Amino "O to give good dynamic P ratac1- water resistance. q j Paraflow 0.5 The thickened lubricants of theinvention are useful in Orthbleum c300 0-5 is many field greaseapplications. In the cn'tcial field of l lubricating (2000 SSU wheelbearing lubricants, these greases have performed at 100 F.) 85. 92 verysatisfactorily. Other successful field-applications in- '465 volumepercent solvent-extracted bright stock (78 elude chassis lubrication,general ball and roller heal" 5 %y% Percent Solvent-extracted bright ingapplications, foundry ladle trunnion bearings, phonograph bearings,textile spinning wheels, cam followers, 'P a z Paraflow and orthokumV300 i' f kiln car bearings, farm equipment, worm gear-radar and m hs'imt'ocelt Amme and tennae, outdoor playground equipment, shakerscreens tol then 'were blended and the preparation mixed at and gearsand mixing vessels. 0 f sixty minutes Overall: including the time Thegreases of the invention are characterized by their necessary to a fSamocelease and reproducibility of preparation and their high Shellpenetratlon? were taken 9 all of the grease static and dynamic waterresistance and high tempera- P S coljlcluslm P the InlXlIlg cycle Secondture consistency stability. In addition they have excel- ShellPenetration Obtamed after the grease had Stood lent oxidation resistanceand mechanical stability. All of ovelmght- The Standard ASTM 0 and 60stroke P 7 these are requisites for amultipurpose lubricating grease,trations also were taken after the grease had stood over- Testing thehigh'temperamre Stability f the thickened mght- The results are glven infollowmg table: lubricants of the invention by heating the greases to400 T B 'VIII F is an extreme test inasmuch as the highest temperatureto which a grease is subjected under even extraordi- Initial 241m 241mASTM nary conditions of use is about 300 F., but the. temper- Example, Am 1 Shell Shell Penetrations ature was adopted as a suitable teststandard because a 'pm. ii ii ii ii grease stable at 400 F. definitelywill have thestability Ostrokes 60 str necessary to withstand heating'to300 F. It will be understood that for normal purposes the thickenedlubri- Percmtfi 123 120 269 274 cants of the invention need not bestable at temperatures 3 137 136 285 290 above about 300 F. and that thegreases of the invention lg at least meet this requirement. Where theterm high 14 184 190 334 344 temperature stability is used, it will beunderstood to 16 8 400 416 I mean that the thickened lubricant is stableagainst loss of consistency at temperatures of at least 300 F. Based 011the Weight SantoceL The Shell penetrations are in accordance with theShell The greases were tested for high temperature stability, MicroconePenetration Test, Institute Spokesman and showed satisfactory hightemperature stability char- (NLGI), volume VI, Number 12, page 1 (1943).acteristics after five cycles. Furthermore, those greases The Sohiomicropenetration technique employed recontaining the higher amounts ofAmine O which had quired a microcone and cup. The microcone wasspecialgiven low grease yields stiffened with the heating during 1ybuilt, and its dimensions are compared in Table II with the test,compensating for the low yield therein. those of the standard ASTM cone,ASTM Designation The water resistance characteristics of the greaseswere 217-48, described on page 143 of the November, 1948 checked by astatic Water test and the dynamic Water edition of D-2 Specificationsfor Petroleum Products.- test in the ASTM worker. The results are shownin the The cone and grease cup employed in obtaining the test followingtable: results required a minimum sample size of 35 ml.

TABLE IX Dynamic water resistance Percent Exglnple igi n e Static30-minute boiling water test Shell pens.

. I Results Orig. H20

6 Very poorconsiderable emulsion-doses grease characteristics. 8Poor-considerable emulsion-loses grease-like characteristics. 10 vGood12 d Oil-in-water emulsion-inverted. 14 do Water-in-oil free HzO-stilladhesive. 16 280 108 Water-in-oil emulsion small amount free HzQ-stilladhesive.

TABLE X MIOROCONE DIMENSIONS ASTM SOHIO Cone Cup Gone Cup Diameter, mm-65 78 20 43 Height, mm. l7 Depth, mm- 65 24. Surface, sq. m 4, 778 6201, 470 Volume, cc 290 35. (3 Gone diam./cup surface 0.136 O. 136 Goneheight/cup depth. 0. 693 Weight of assembly. gnis- 150 1 13 Weight ofassembly/sq. mm. cone surface 0. 021 0. 021

1 Calculated.

All parts and percentages are by weight of the thickened lubricantunless otherwise indicated.

I claim:

l. A thickened lubricant of high temperature stability and good dynamicwater resistance, consisting essentially of a mineral lubricating oil oflubricating viscosity as the major component, a finely-divided inorganicwatersusceptible oil thickener in an amount sufficient to impart agrease consistency to the oil, a water-insoluble oilmisciblepolyalkylene glycol diether having a viscosity at 100 F. within therange of from 40 to 500 SSU, and a Water-insoluble oil-dispersiblecationic surface-active imidazoline having an aliphatic groupsubstituted at the 2-position and a hydrophilic group substituted at the1- position of the imidazoline, said glycol diether being in an amountwithin the range from 0.25 to about 2.5% by Weight of the thickenedlubricant, and said irnidazoline being in an amount Within the rangefrom 4 to 14% by weight of the inorganic Water-susceptible oilthickener, each being in amounts suflicient in combination to imparthigh temperature stability and dynamic Water resistance to the thickenedlubricant.

2. A thickened lubricant in accordance with claim 1 in which thepolyalkylene glycol diether is a mixed po1yethylene-1,2-propylene glycoldiether.

3. A thickened lubricant in accordance with claim 1 in which theimidazoline is I-B-hydroxyethyl-Z-heptadecenyl imidazoline.

4. A thickened lubricant in accordance with claim 1 in which theinorganic oil thickener is a silica aerogel.

5. A thickened lubricant of high temperature stability and good dynamicwater resistance, consisting essentially of a mineral lubricating oil oflubricating viscosity as the major component, a finely-divided silicaaerogel in an amount suflicient to impart a grease consistency to theoil, a water-insoluble oil-miscible mixed polyethylene- 1,2-propyleneglycol diether having a viscosity at 100 F. Within the range of from 40to 500 SSU, and a'water-insoluble oil-dispersible cationicsurface-active imidazoline having an aliphatic group substituted at the2-position and a hydrophilic group substituted at the 1-position of theimidazoline, said glycol diether being in an amount within the rangefrom 0.25 to about 2.5% by weight of the thickened lubricant, and saidimidazoline being in an amount within the range from 4 to 14% by weightof the inorganic water-susceptible oil thickener, each being in amountssufiicient in combination to impart high temperature stability anddynamic water resistance to the thickened lubricant.

6. A thickened lubricant in accordance with claim 5, in which theimidazoline is I-B-hydroxyethyl-Z-heptadecenyl itnidazoline. 7

References Cited in the file of this patent UNITED STATES PATENTS2,554,222 Stross May 22, 1951 2,573,650 Peterson Oct. 30, 1951 2,652,365Moore et al. Sept. 15, 1953 2,655,476 Hughes et al Oct. 13, 19532,711,393 Hughes et a1. June 21, 1955

1. A THICKENED LUBRICANT OF HIGH TEMPERATURE STABILITY AND GOOD DYNAMICWATER RESISTANCE, CONSISTING ESSENTIALLY OF A MINERAL LUBRICATING OIL OFLUBRICATING VISCOSITY AS THE MAJOR COMPONENT, A FINELY-DIVIDED INORGANICWATERSUSCEPTIBLE OIL THICKNER IN AN AMOUNT SUFFICIENT TO IMPART A GREASECONSISTENCY OF THR OIL, A WATER-INSOLUBLE OILMISCIBLE POLYALKYLENEGLYCOL DIETHER HAVING A VISCOSITY AT 100*F., WITHIN THE RANGE OF FROM 40TO 500 SSU, AND A WATER-INSOLUBLE OIL-DISPERSIBLE CATIONICSURFACE-ACTIVE IMIDAZOLINE HAVING AN ALIPHATIC GROUP SUBSTITUTED AT THE2-POSITION AND A HYDROPHILIC GROUP SUBSTITUTED AT THE 1POSITION IN THEIMIDAZOLINE, SAID GLYCOL DIETHER BEING IN AN AMOUNT WITHIN THE RANGEFROM 0.25 TO ABOUT 2.5% BY WEIGHT OF THE THICKNED LUBRICANT, AND SAIDIMIDIAZOLINE BEING IN AN AMOUNT WITHIN THE RANGE FROM 4 TO 14% BY WEIGHTOF THE INORGANIC WATER-SUSCEPTABLE OIL THICKENER EACH BEING IN AMOUNTSSUFFICIENT IN COMBINATION IN IMPART HIGH TEMPERATURE STABILITY ANDDYNAMIC WATER RESISTANCE TO THE THICKENED LUBRICANT.